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Single Family ResidenceResidential
$1,171,277$521 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 92How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Oct 21, 2026
Last sold for $384,500 on Apr 24, 2012

521 W UNION ST

BOISE, ID 83702
4
Beds
2.5
Baths
2,246 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
0.1 ac
Lot SizeThe size of the land the home sits on, from county records.
1910
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
1
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$1.2M
$1.1M low$1.3M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$384,500 · Apr 24, 2012

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$6,932 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$861,900 (2026)
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$877,100
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$861,900

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Bi-Level
CountyADA
Effective Year BuiltAn adjusted build year that accounts for condition and major remodels. A big renovation can make a home count as newer than it is.2005
Lot (acres)The size of the land the home sits on, from county records.0.10
RoofThe main material covering the roof, such as asphalt shingle or tile.Composition Shingle
HeatingThe type of heating system in the home.Yes
CoolingThe type of cooling or air conditioning in the home.Yes
FireplaceWhether the home has a fireplace, and what kind.Yes
GarageWhether the property has a garage, and details like whether it is attached to the home.Garage, Detached
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Porch · 35 ft²

Transaction History(5)

Sales and refinances filed with the county for this home. Not every transfer is a normal sale, so check the type before comparing prices.

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

H
Boise Senior High SchoolB
High · Grades 9–12 · 0.4 mi
E
Longfellow Elementary SchoolA+
Elementary · Grades PK–6 · 0.4 mi
M
North Junior High SchoolA-
Middle · Grades 7–9 · 0.5 mi

District: Boise City Independent School District 1

Neighborhood · ZIP 83702These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.138
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.113
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.69

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.92%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.38%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.9.2%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.2%
PopulationHow many people live in this area.27,736
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.404 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$89,131
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$125,125
Average tempThe average temperature here across a full year.48°F
Annual precipHow much rain and melted snow falls here in a typical year.21 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.64%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

521 W Union St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Worth more than 94% of homes in Ada County
  • Costs more per square foot than 97% of homes in Ada County
  • Has a smaller lot than 89% of homes in Ada County
  • Among the oldest homes in Ada County

What homes are worth in Boise 83702

Each bar is how many homes fall in that price range. The marker is this home.

This home
$317K$2.4M

This home is worth more than 75% of homes in Boise 83702.

How it measures up in Boise 83702

The dot is this home. The mark in the middle is the typical home in Boise 83702.

Estimated value$1,171,277
CheaperTypical $846,194Pricier

Pricier than 75% of homes nearby

Price per ft²$521
CheaperTypical $474Pricier

Pricier than 65% of homes nearby

Living area2,246 ft²
SmallerTypical 1,903 ft²Bigger

Bigger than 63% of homes nearby

Lot size0.1 ac
SmallerTypical 0.14 acBigger

Bigger than 22% of homes nearby

Year built1910
OlderTypical 1952Newer

Newer than 16% of homes nearby

How 521 W Union St ranks against every home in each area.
MeasureThis homeBoise 83702Ada County
Estimated valuepricier than$1,171,27775% of homes94% of homes
Price per ft²pricier than$52165% of homes97% of homes
Living areabigger than2,246 ft²63% of homes64% of homes
Lot sizebigger than0.1 ac22% of homes11% of homes
Year builtnewer than191016% of homesalmost no homes

About 521 W Union St

How much is 521 W Union St, Boise, ID worth?

The TopHap Estimate for 521 W Union St, Boise, ID is $1,171,277 as of Oct 21, 2026. The likely range is $1,080,849 to $1,261,705. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 521 W Union St, Boise, ID last sell?

521 W Union St, Boise, ID last sold on Apr 24, 2012 for $384,500, according to the county's recorded deed.

How big is 521 W Union St, Boise, ID?

521 W Union St, Boise, ID has 4 bedrooms, 2.5 bathrooms, 2,246 square feet of living space and a 0.10-acre lot.

When was 521 W Union St, Boise, ID built?

521 W Union St, Boise, ID was built in 1910, making it 116 years old. It is a bi-level home. The building has 2 stories.

What schools serve 521 W Union St, Boise, ID?

521 W Union St, Boise, ID is assigned to Boise Senior High School (high), rated B; Longfellow Elementary School (elementary), rated A+; North Junior High School (middle), rated A-. All sit in Boise City Independent School District 1. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 521 W Union St, Boise, ID compare to other homes in Boise 83702?

Among the 8,369 homes in Boise 83702, it is worth more than 75% of them ($1,171,277 against a typical $846,194), its price per square foot is higher than 65% of them ($521 against a typical $474), it is bigger than 63% of them (2,246 ft² against a typical 1,903 ft²), its lot is bigger than 22% of them (0.1 ac against a typical 0.14 ac) and it is newer than 16% of them (1910 against a typical 1952). Measured against all of Ada County, it is worth more than 94% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 521 W Union St, Boise, ID?

The 2025 property tax bill for 521 W Union St, Boise, ID was $6,932. The county assessed it at $861,900.

More homes on W Union St

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